A boy who died while on an outing with his Beaver Scout group could have been missing for more than 30 minutes.

During the second day of the inquest into the death of Alan Lock, from Acton, it emerged how only one head count had been carried out during the supervised walk.

The six-year-old, who had attended Acton Primary School, died on June 16, 2009, after he ended up in the River Stour, close to Friars Meadow, Sudbury.

As Robert Horner, a lawyer representing the family, tried to establish the time span between events, it was suggested Alan could have lain undiscovered in the water for more than half an hour.

The inquest also heard how on the second bridge along the old railway line walk a metallic sounding bang had been heard, but it was “dismissed” by the two adult supervisors who heard it. It was when the group was making its way back across this bridge at the end of the outing that a child spotted a pair of shoes sticking out of the river, which turned out to be Alan, of Cedar Walk.

Four adults had supervised the 18 Beaver Scouts which was heard to meet the required adult to child ratio, but only one head count had been carried out during the walk.

Speaking at the inquest Alison Wadley, who at the time was assistant Beaver leader in training with 1st Acton and Waldingfield Scout Group, said head counts should be done when you leave one space and enter another.

The inquest heard how the group had met at the Kingfisher Leisure Centre in Sudbury at about 6pm on the evening of the tragedy and headed to Friars Meadow where a scavenger hunt took place to find sticks and flowers.

The hunt ended at about 6.20pm, Ms Wadley said, when the group left Friars Meadow at the first bridge and a head count was taken.

Ms Wadley - who had also carried out the registration at the start of the outing - had counted all 18 children.

Steven Norman, who had been a volunteer helper, had helped Alan go to the toilet just after the first bridge and they then carried on with the walk.

At the second bridge - which is about 100 metres from the first - the inquest heard how a “metallic banging sound” was heard.

Both Ms Wadley and Mr Norman heard the noise and they looked to see what had caused it, but had heard no splash and saw no ripples. The group then carried on with their walk.

Speaking in the inquest Mr Norman said: “If there was any indication that this had had any danger element related to it we would have stopped.”

Ms Wadley admitted in the inquest a head count should have been carried out when the group came together at the end of the second bridge.

She said: “It wasn’t long since I had done the first one. I didn’t think in my opinion we had lost any children.”

She added: “In hindsight, yes, I should have done one, but I didn’t.”

Mr Horner had said the hunt had finished at about 6.20pm while Alan was found in the water at about 7.05pm.

The inquest has heard of no concrete evidence that the youngster fell from the bridge.

The inquest continues today.